Beginner Gardening: Zinnia, 1 by David_Paul

David_Paul wrote:
Is that a white power on the leaves? You could have mildew. Larger plants keep going for a while with it but smaller ones weaken faster. I grew Purple Prince this year and had a time with the mildew. Baking soda kept it under control most of the summer. In mid-august I slacked off the spraying and while the flowers kept coming (these plants were huge..some over 5 feet) the foliage looked terrible and I pulled them out.

A before and after view of a 35 foot row of Purple Prince zinnias: